JPS62186990A - Method for preventing sticking of marine living matter - Google Patents

Abstract

PURPOSE:To permit long-term continuous operation of a cooling sea water system by impressing very high frequency high-voltage pulses to the sea water passing the inlet part and inside of the cooling sea water system to exterminate or paralyze the larva of the sticking marine living matter in the sea water. CONSTITUTION:The cooling sea water system for a power plant is constituted of, for example, a sea water intake port 1, an intake path 2, a circulation pump 3, an intake side pipeline 4, a condenser 5, a cooling water cooler 6, a release side pipeline 7, a release side water channel 8, etc. Devices 10, 20 for impressing the very high frequency high-voltage pulses are respectively provided to, for example, the inlets of the sea water intake port 1 and the intake side pipeline 4 in this case. The larva of the sticking marine living matter in the sea water flowing into the system from the intake port 1 as shown by an arrow A is exterminated or paralyzed in the stage of passing the devices 10, 20. The sticking and growing of the marine living matter into the wall surfaces of the intake path 2 and the intake pipeline 4 are thereby prevented. As a result, there are no problems in environmental protection and the smaller energy consumption is required. The long-term continuous operation of the cooling sea water system is made possible.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention is applied to cooling seawater systems such as seawater pipes that lead in and out of cooling seawater, heat exchangers that use seawater as cooling water, and other plants. Concerning methods for preventing biofouling.

[Conventional technology]

In cooling seawater systems such as seawater pipes that lead in and out of cooling seawater, heat exchangers and other plants that use seawater as cooling water,
A phenomenon occurs in which marine organisms adhere to seawater channels or grow after adhesion, increasing channel resistance and heat transfer resistance, and in extreme cases can clog the channel itself. For this reason, various countermeasures have been conventionally taken for the flow paths of cooling seawater systems. Among them, the representative ones are:
There are chemical antifouling methods and physical antifouling methods. The chemical antifouling method uses mercury and arsenic in the structure that forms the flow path.

There are methods of applying antifouling paint containing compounds such as copper and organic tin, methods of injecting drugs such as sodium chloride hypochlorite into seawater, and methods of electrolytically decomposing seawater itself as an electrolyte, which is generated at the cathode. This is a method that uses the killing effects of chlorine and chlorate ions to kill marine life. Physical antifouling methods include methods such as applying ultrasonic waves, irradiating ultraviolet rays, and increasing flow velocity, and these methods are used to prevent marine organisms from adhering to the surface.

[Problem that the invention seeks to solve]

In the conventional chemical antifouling method described above, substances such as chlorine, tin, and copper are mixed into the discharged seawater, resulting in environmental protection problems. In addition, physical antifouling methods have problems such as high energy consumption1 and high power costs, and are rarely put into practical use.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a method for preventing the adhesion of marine organisms, which does not cause problems in terms of environmental protection, consumes less energy, and enables long-term continuous operation of a cooling seawater system.

(Means for Solving the Problems) The present invention is characterized by taking the following measures in order to solve the above problems and achieve the objectives.

That is, at the entrance or inside of the cooling seawater system, an extremely short high voltage pulse (high voltage pulse with an extremely short pulse width) is applied to the seawater passing through the cooling seawater system to kill or kill the larvae of sea creatures attached to the seawater. It is characterized by causing paralysis.

[Effect]

By taking such measures, a high current flows within the larvae of sea creatures in seawater due to the applied extremely short high voltage pulses, which can reliably kill or paralyze the larvae, and also pose a problem of environmental pollution. Therefore, only a small amount of energy is required.

〔Example〕

FIG. 1 is a system diagram of a cooling seawater system for a power plant, showing an embodiment of the method for preventing adhesion of marine organisms of the present invention. In the figure, 1 is the seawater intake, 2 is the intake channel, 3 is the circulation pump, 4 is the intake pipe, 5
is a condenser, 6 is a cooling water cooler, 7 is a water discharge side pipe, and 8 is a water discharge side waterway.

Very short high voltage pulse application devices 10 and 20 are installed at each inlet of the seawater intake 1 and the intake pipe 4, respectively. Each of these ultra-short high voltage pulse application devices @10.20
A power supply device 11 and 21 are connected to each of them.

In the cooling seawater system for power plants configured in this way,
Im in the seawater flowing in from seawater intake 1 as shown by arrow A
The larvae of living things are treated with an extremely short high voltage pulse application device ff110.2.
0, the intake channel 2 will die or become paralyzed.
Adhesion and growth on the wall surface of the water intake pipe 4 can be prevented.

"Experiment Example 1" Brine shrimp (this creature is a small shrimp larva with a length of about 500 cm to 1 aa+, and is commonly used in attachment effect tests as a representative of larval adherent sea creatures) was used as a representative of larvae of adherent marine organisms. Then, an extremely short high voltage pulse was applied using the experimental apparatus shown in FIG.

In FIG. 2, 31 is an ultra-short high-voltage pulse generation power supply device;
32 is a high voltage application electrode, 33 is a ground electrode, and 34 is a container in which test larvae are placed, 11,120 m wide, 130 m wide, and 5 deep.
It is about m. Put 20 brine shrimp in the container 34, voltage 30KV, pulse width 300nsec
A high voltage pulse of 2 seconds was applied. As a result, it was found that there was no movement even after 5 minutes had passed after the application of the high voltage pulse, indicating that the animal had died. Note that the applied voltage was 20KV1
Immediately after the application, all 20 of them stopped moving, but 5 minutes later, 6 of them recovered their movement, confirming that they had fallen into a poetic state of paralysis.

"Experimental Example 2" Using actual seawater, the adhesion prevention effect of ultra-short high voltage pulses was tested using an experimental apparatus as shown in FIG.

In Fig. 3, 35 is a seawater intake pump, 36 is a seawater tank having a head of a certain height, and 37 is 2 m in length.

It is a steel pipe with an inner diameter of 80a* and whose inner surface is coated with tar and epoxy, through which seawater to which extremely short high voltage pulses are applied flows. 38 is a steel pipe with the same specifications as 37, through which untreated seawater flows. 39 is a control valve provided in each steel pipe 37 and 38.

As a result of a one-year continuous water flow experiment using this device, the total wet weight of adhered seawater was 200 g for pulse applied steel pipe 37.
In contrast, it was 4800Q for untreated steel pipe 38. In addition, the number of mussels attached was less than 20 on the pulse-applied steel pipe 37, while on the untreated steel pipe 3
8, it was more than 2000 pieces. Furthermore, the number of fujibbo attached was 51 m on the pulse-applied steel pipe 37, while it was 160 on the untreated steel pipe 38.

From the above experimental results, it was confirmed that the effect of this method on preventing the adhesion of marine organisms is extremely significant.

As explained above, this embodiment has the following effects.

■ Applying ultra-short high-voltage pulses can reliably kill or paralyze attached sea creature larvae that pass through the electrode section.

■Since the adhesion and growth of attached marine organisms to flow channels, heat exchangers, etc. is eliminated, increases in flow channel resistance and heat transfer resistance, and accidents such as blockage of heat exchangers can be prevented.

■By adjusting the application conditions of ultra-short high voltage pulses,
*You can adjust the degree of damage to sea creature larvae.

■Unlike conventional chemical antifouling methods, no harmful substances such as chlorine, tin, or copper are mixed into the discharged seawater, so there are no environmental protection problems.

(2) The pulse width of the ultra-short high voltage pulse is from several + n5 ec to several hundred H, and the energy consumption is extremely low.

■Since the adhesion of marine organisms can be prevented, long-term continuous operation of the cooling seawater system is possible.

Note that the present invention is not limited to the above embodiments. For example, in the above embodiment, the ultra-short high voltage pulse application device was installed at two locations, the seawater intake 1 and the intake pipe 4, but depending on the conditions, it may be installed at only one of them. You may also do so. It goes without saying that various other modifications can be made without departing from the gist of the present invention.

〔Effect of the invention〕

According to the present invention, an extremely short high voltage pulse is applied to the seawater passing through the inlet or inside of the cooling seawater system to kill or paralyze the larvae of attached sea creatures in the seawater. Therefore, it is possible to provide a method for preventing the adhesion of marine organisms, which does not cause problems in terms of environmental protection, consumes less energy, and enables long-term continuous operation of a cooling seawater system.

[Brief explanation of drawings]

Fig. 1 is a system diagram of a cooling seawater system for a power plant showing an example of the method for preventing the adhesion of marine organisms of the present invention, and Figs. 2 and 3 are diagrams showing the experimental equipment of Experimental Example 1 and Practical Example 2, respectively. It is. 1... Seawater intake, 2... Intake channel, 3... Circulation pump, 4... Water intake side pipe, 5... Condenser, 6...
Cooling water cooler W device, 7... Water discharge side pipe, 8... Water discharge side channel, 10.20... Ultra short high voltage pulse application device, 11
．． 21... Electric 8i device, 31... Ultra short high voltage pulse generation power supply device, 32... High voltage application electrode, 33...
Earth electrode, 34... Container, 35... Seawater intake pump, 36... Seawater tank, 37... Pulse application steel pipe, 38... Untreated steel pipe, 39° 40... Control valve. Applicant Sub-Agent Patent Attorney Takehiko Suzue Figure 2 Figure 3

Claims (1)

[Claims] A seawater system characterized by applying an extremely short high voltage pulse to the seawater passing through the inlet section and/or inside the cooling seawater system to kill or paralyze larvae of attached sea creatures in the seawater. Biofouling prevention method.